java连接数据库并显示数据

 1. 导入jdbc包

  java要连接MySQL数据库需要用到JDBC工具(mysql-connector-java-5.1.39-bin.jar)，这是一个jar包，不同的数据库对应不同的jar包，这里用的是MySQL数据库jar包，导入很简单，鼠标对项目右击 - Build Path - Configure Build Path - 右侧选Libraries - Add External JARs,选择正确的jdbc包就行了。

2. 创建数据库(示例: 数据库名studentdb , 表名stable)

3 新建属性及构造方法类(stuInfo.java)

public class stuInfo {
	private int sno;
	private String sname;
	private String sex;
	private int age;
	
	public int getSno() {
		return sno;
	}
	public void setSno(int sno) {
		this.sno = sno;
	}
	public String getSname() {
		return sname;
	}
	public void setSname(String sname) {
		this.sname = sname;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	
	public stuInfo(){
		
	}
	public stuInfo(int sno, String sname, String sex, int age) {
		this.sno = sno;
		this.sname = sname;
		this.sex = sex;
		this.age = age;
	}
}

3. 新建主类(shoeTest.java)

import info.stuInfo;

import java.util.ArrayList;
import java.sql.*;

public class showTest {

	
	public static void main(String[] args) {
		ArrayList list = getAllStus();
		
		if(list.size() == 0){
			System.out.println("暂无数据");
		}else{
			for(stuInfo s: list){  //遍历集合数据
				System.out.println(s.getSno()+"\t"+s.getSname()+"\t"+s.getSex()+"\t"+s.getAge());
			}
		}

	}
	
	//采用集合的方法，返回数据集合
	public static ArrayList getAllStus(){
		ArrayList stulist = new ArrayList();
		
		String url = "com.mysql.jdbc.Driver"; //加载驱动包
		String connectSql = "jdbc:mysql://127.0.0.1:3306/studentdb"; //链接MySQL数据库
		String sqlUser = "root"; //数据库账号
		String sqlPasswd = "*****"; //你的数据库密码
		
		Connection con = null;
		PreparedStatement psm = null;
		ResultSet rs = null;
		
		
		try {
			//加载驱动包
			Class.forName(url);
			//连接MYSQL
			con = DriverManager.getConnection(connectSql,sqlUser,sqlPasswd);
			//执行MYSQL语句
			psm = con.prepareStatement("select * from stable");
		    rs = psm.executeQuery();
			System.out.println("编号"+"\t"+"姓名"+"\t"+"性别"+"\t"+"年龄");
			while(rs.next()){
				stuInfo s = new stuInfo();
				s.setSno(rs.getInt(1));
				s.setSname(rs.getString(2));
				s.setSex(rs.getString(3));
				s.setAge(rs.getInt(4));
				
				stulist.add(s);	
			}
			
			//关闭数据库连接
			rs.close();
			psm.close();
			con.close();
			
		} catch (Exception e) {
			System.out.println("显示所有数据报错，原因："+e.getMessage());
		}
		
		return stulist;	
	}
	

}

4. 运行测试